Typically if you don't see overlays or overlays without data the following issues come to mind.
First, let me explain this--
Activity Map when the plugin is run it scans the dom for all of the links for the following information (page, region, link)This is how it knows where to place the overlay and do the rankings.
2. If page, region, link are the same or if region and link are the same it won't be able to identify where to put the overlays and put them all over the same one.
You can check this by pulling up the network tab in dev tools in your browser.
filter by b/ss
click the links and view the image request
here you should see activity map data
3. If this is a new implementation you may be seeing data show up now. If this was barely implemented at the point of running the plugin you won't have any historical data to have the overlays to show up.
If this is still an issue after this please open a client care ticket by emailing: